Present exhaust devices for mounting at the outlet of the guide vane stage of a gas turbine upstream from its exhaust duct are constituted by a cone whose opening is terminated by a series of concentric deflector blades.
This arrangement cannot completely deflect the exhaust gas which therefore takes up a privileged direction lying at about 50.degree. on either side of the axis. In addition, given the real outlet cross-section, the exhaust speeds are high and nonuniform, with speeds which may differ by a factor of more than two. Further, the very shape of the vanes, in addition to being difficult to make and difficult to make mechanically strong enough, gives rise to local speed excesses which generate considerable aerodynamic turbulence. Such exhaust gases are therefore taken up into a silencer exhaust duct for attenuating the noise they produce under poor aerodynamic conditions. It is not possible to obtain a uniform field of speeds in the inlet gas to the silencer exhaust duct, thereby giving rise firstly to a poor feed to the air paths and thus to poor acoustic efficiency in the silencer exhaust duct, and secondly to the formation of aerodynamic turbulence which generates low frequency noise and vibration that is very difficult to attenuate and may even give rise to damage to the apparatus.
The aim of the present invention is to provide a turbine outlet with a uniform distribution of gas flow, with exhaust speeds that are well distributed and reduced, with a reduction in major turbulence, and with a reduction in noise level.